High voltage powerlines have been constructed to extend from spaced towers high above terrain which is practically inaccessible to land vehicles. In recent years, a number of methods and devices have been developed to facilitate the repair or high voltage powerlines by helicopter. U.S. Pat. No. 4,637,575 to Yenzer shows a prior art helicopter repair device and method for repairing high voltage powerlines.
Powerlines are often suspended from each support tower by elongate insulators which attach to a yoke plate which in turn supports a plurality of powerlines. Attached to the yoke plate are support shoes, each of which receives and supports a powerline. Often, prolonged vibration of a powerline will cause strands of the line to break in the area where the line engages the support shoe, and in some cases it is desirable to replace the support shoe as well as repair the powerline. These tasks have been extremely difficult and time consuming to perform in the past, as the tension on the powerline must be broken so that the line can be lifted out of the support shoe to facilitate line repair and/or shoe replacement. The tension on the line cannot be easily broken by two linemen with hand winches balanced on the line on either side of the yoke plate who attempt to draw the line toward the yoke plate. In an attempt to alleviate this problem, some linemen have tried to winch the line upward from the crossbar at the top of the tower, but this is not an effective method for breaking the tension on the line. Not only does it require the winching apparatus to extend over a long distance, but it further places a lineman on the tower crossbar far removed from the area where the repair is to be made.
Consequently, the need has arisen for a method and apparatus which will permit linemen to quickly and easily break the tension on high voltage powerlines while remaining in the area of a yoke plate where the repair is to be made.
It is a primary object of the present invention to provide a novel method and apparatus for high voltage powerline repair which includes temporarily attaching a template to the yoke plate to receive and position winch lines on opposite sides of a yoke plate directly above a powerline. The winch lines extend from the template to a hand winch and from the hand winch to attachments with the powerline on opposite sides of the yoke plate.
Another object of the present invention is to provide a novel and improved method and apparatus for high voltage powerline repair wherein winch lines are positioned above and on opposite sides of a yoke plate and are directly aligned above a powerline supported by the yoke plate. The winch lines extend downwardly at an angle to connections with the powerline spaced outwardly on opposite sides of the yoke plate, and are used to draw the powerline upwardly toward the yoke plate to raise the powerline out of contact with the yoke plate.
A still further object of the present invention is to provide a novel and improved template for powerline assembly repair which includes a substantially T shaped body having a lower section for engaging a yoke plate between the powerlines supported thereby and an upper section which extends laterally outward on either side of the lower section. The upper section supports oppositely disposed winch line connectors with a pair of oppositely disposed winch line connectors aligned above each powerline supported by a yoke plate.
These and other objects of the present invention include a method and apparatus for powerline assembly repair where a powerline is supported from a support assembly, such as a yoke plate support assembly, which is suspended from a tower. The basic method involves concurrently drawing the powerline upwardly at an angle toward a level above the support assembly from first and second positions on the powerline spaced outwardly from the support assembly on opposite sides thereof. This breaks the tension on the powerline and raises it out of contact with the support assembly so that repairs can be made before the powerline is returned to contact with the support assembly. To enable drawing the powerline upwardly toward a level above a yoke plate support assembly, a template is attached to the yoke plate support assembly in spaced relation to the powerlines supported by the yoke plate support assembly with the template extending above the yoke plate support assembly but within the field of safe working distance for the energized powerlines. A first winch assembly is extended from a first connection with a first side of the template above the yoke plate support assembly to extend downwardly at an angle to a first connection with the powerline at a point spaced outwardly from a first side of the yoke plate support assembly. A second winch assembly is extended from a second connection with a second side of the template opposite to the first side and above the yoke plate support assembly downwardly at an angle to a second connection with the powerline at a point spaced outwardly from a second side of the yoke plate support assembly which is opposite to the first side of the yoke plate support assembly. The first and second connections with the template are in alignment with each other and are aligned with the powerline, while the first and second connections with the powerline are substantially equally spaced from the yoke plate support assembly. The winch assemblies are concurrently operated to draw the powerline upwardly toward the template to break the tension on the powerline and raise it out of contact with the yoke plate support assembly.